A tool changer provided in an NC machining tool has a plurality of magazine pots in which various sorts of tools are loaded, and is arranged so that desired one of the tools is taken out from the associated magazine pot under control of an instruction and then mounted to the NC machine tool for machining.
The following is an example of a conventional NC machining program for the selection of tools.
* T01
* G43H01
* S543M03
* F100
T01: Specify the magazine address of each machine, in this example, to "1".
G43: Correct tool length
H01: Select a correction number H01.
S543: Set main shaft rotational speed to 543 rpm
M03: Forward rotation command
F100: Set feed command value to 100 mm/min.
In the conventional NC machining program, the T code command is to specify a magazine address, not to select a tool directly. Command parts corresponding to correction commands and machining condition commands such as G43H01, S543M03, F100, etc. vary depending on a tool to be used, ability of each machine tool and a material of work to be machined. These command parts are set by an operator at appropriate values for each operation, taking a tool to be used into consideration.
A large number of NC machine tools are generally installed in a factory, each NC machine tool being provided with a tool changer. However, the correspondence between a tool and its magazine address is determined arbitrary at each tool changer and thus there has been no standard for the correspondence between the tool and magazine address. For example, there occurs such a situation that the magazine address 1 of one tool changer corresponds to an end mill tool having a diameter of 25 mm while the magazine address 1 of another tool changer corresponds to a milling cutter tool having a diameter of 100 mm. For this reason, in the conventional NC machining program in which the selection of tools is preformed by specifying a magazine address in a T code command, it is necessary to modify the T code command part for each NC machine tool.
The program modification requires not only change in the T code command part but also change in such command parts as G43H01, S543M03, F100, etc., which results in that each time a tool is changed, it is necessary to modify the machining program to a large extent.
As the number of types of machining works has been increased recently, there has been a tendency that the number of tools exceeds the tool accommodation capacity of the magazines.
There has bee a swing head device for a composite machine tool capable of preforming various types of machining including boring, turning and milling. The swing head device comprises a turntable on which a work to be machined is mounted and a swing head positioned above the turntable on which a tool is mounted. The turntable is movable horizontally in X-axis and Y-axis directions and the swing head is movable vertically in an Z-axis direction and rotatable around a pivot axis in a Y-Z plane.
FIG. 13 illustrates an example of a conventional swinging mechanism for turning the swing head. In the illustrated swinging mechanism, a rack d vertically moved by a swing cylinder c is meshed with a pinion b provided to a pivotable swing head a so that the swing cylinder c rotates the swing head a through the rack d and the pinion b. A curving coupling e is provided between the swing head a and a main shaft head (not shown) so that the curving coupling e fixes the swing head a at a desired indexing position.
In the conventional swing head device, a proximity switch or a limit switch or a lead switch is provided in the vicinity of the swing cylinder to detect that the swing head is located at an indexing position. When the number of indexing positions is increased, the number of the switches correspondingly increased. Therefore, the conventional swing head device is disadvantageous in that the size of the device becomes large, its arrangement become complicated and the cost becomes high.
In view of such circumstances, it is an object of the present invention to provide an NC-machining controller which can perform centralized control on the tool information, can use a common machining program to different machine tools, and can improve working efficiencies of the respective machine tools.
Another object of the present invention is to provide a swing head device of a composite machine tool which can accurately detect indexing positions of the swing head with a simple and inexpensive arrangement.